Radial vane pump mechanism



April 27, 1948. HQ B. MILLER 2,440,593

RADIAL VANE PUMP MECHANISM Filed Oct. 23, 1946 4 Sheets-Sheet 1 gvwmfmHARRY B. MILLER April 27, 1948. H. a. MILLER 2,440,593

RADIAL VANE PUMP MECHANISM Filed 001;. 23, 1946 4 Sheets-Sheet 2 v 25gvwcmkw a HARRY B. MILLER w w w A n'n 27, 1948.

H. B. MILLER RADIAL VANE. PUMP MECHANISM Filed Oct. 23, 1946 4Sheets-Sheet 3 QvWa/MM HARRY B. MLLER April 27, 1948.

mom. mm rum MEcmmIsu Filed Oct. 23, 1946 48heeis-Sheet 4 FIG. l7;

Jami/WM HARRY B. M'ILLER H. B. MILLER 2,440,593-

Patented Apr. 27, 1 948 UNITED STATES PATENT OFFICE RADIAL VANE PUMPMECHANISM Harry B. Miller, Providence, R. I. Application October 23,1946, Serial No. 705,180 2 cla ms. (01. 230-140) This invention relatesto rotary pumps of the positive displacement type in which a radial vaneseparates the intake and pressure chambers of the pump. Moreparticularly, the invention relates to a pump in which the outer memheror cylinder rotates, and the inner member or rotor also rotates, eachabout its own center but in eccentric relationship to each other, so asto form a crescent-shaped pumping chamber between the two members. Thischamber is divided into intake and pressure portions by the radial vane,and the sides of the crescent-shaped pumping chamber are enclosed bysuitable end plates.

I1; is well known that pumps of this character are advantageous becauseof their freedom from vibration and the absence of sliding frictionbetween the piston and cylinder. Since the outer cylinder and the rotorboth rotate, each about its own center, there is freedom from vibrationand inertia effects, and, since the two parts are in tangential relationto each other, and the slight contact, if any, is a rolling one, thewear is reduced to a minimum. It has been the usual practice in theprior art to cause actual rolling contact between the outer cylinder andthe rotor, but according to the present invention it is proposed tomaintain a very slight clearance between these members and to seal thisclearance by,a thin oil film. In this way not only are frictionaleffects eliminated, but adequate scaling is accomplished as an incidentto the lubrication of the pump and wear due to the usual contact isnon-existent.

In pumps of the type under consideration where both the outer cylinderand the rotor rotate together, it is the usual practice to secure theradial vane to the outer cylinder and to connect it in driving relationwith the rotor through a vane bearing which is cylindrical in crosssection and contains a longitudinal slot which embraces the faces of thevane, producing substantial frictional contact during the operation ofthe pump. In known constructions the vane bearing rocks back and forthas the parts move so that the sides of the vane, as well as the slot inwhich it moves, are subject to serious wear with continuing tendency toleakage. Inasmuch as it is desirable to reduce this frictional contacttoa minimum, it is considered to be good engineering practice to reducethis rocking action by so arranging the parts that the vane is neverwithdrawn radially outward beyond the geometrical center of thevanebearing during the operation of the pump. Should it go beyond thiscenter, the bearing is canted so as to rapidly increase the frictionalcontact and consequently the wear between the faces of the vane andtheir area of contact with the bearing. This required relation of partsautomaticallyimposes a serious handicap on machines of this type becauseit limits the amount of pump displace-merit,

which can be secured without unduly weakening the metal sections of thepump. This is particularly true of the radial metal section existent inthe rotor between its bearing and the vane hearing in which the vanemoves. As will be pointed out hereinafter, the present constructionmaintains the faces of the vane in parallelism with the surfaces of thevane bearing with which it cooperates, and an arrangement is 'providedwhereby rocking is completely eliminated and the vane partakes ofstraight line movement only with respect to the vane bearing. By theprovision of a vane of peculiar shape and a cooperating bearing ofappropriate shape, the dlsplacement of the pump may be materiallyincreased over that which is possible with prior art constructions.Whereas in prior art constructions the displacement of the pump wasdetermined by the amount of radial movement of the vane in the vanebearing, practice of the present invention removes that limitation.Consequently the capacity of a pump of given outside dimensions may beincreased as indicated. It is also proposed to provide the working partswith adequate lubrication and to provide a pressure seal for the rotorof the pump as an incident to the normal operation of the parts withoutthe addition of any extraneous means. This pressure seal produced inthis manner permits pump operation at pressures or vacua greatly inexcess of those possible with existing apparatus, and

parts, where this would not be possible in prior art pump constructions,particularly those of the reciprocating type. It goes without sayingthat apparatus of this type can operate either as a pump or as a motor,depending upon whether it is used as a source of pressure, or whetherpres-.

sure is supplied to it.

It will be apparent from the preceding description that an importantobject of the present inventionis to produce a simple compact devicemade up of a minimum number of parts and hence capable of manuafcture ata minimum cost. Only a few of the advantages of the invention have beenmentioned-but many others will be apparent from the followingdescription when it is read in conjunction with the accompanyingdrawings in which:

Figure 1 is a horizontal sectional view of a portion of the assemblyshowing thepump in end elevation Fig. 2 is a central verticalsectionthrough the complete assembly showing the pump parts in the position inFig. 1;

Fig. 3 is a view similar to Fig. l with the pump rotor displaced 180degrees from the position of F18. 1;

Fig. 4 is a central vertical section through Fig. 5 is a view inelevation of one of the end plates showing the intake port;

Fig. 6 is a horizontal sectional view through the pump showing theintake and pressure ports with reference to the radial vane and itsbearing, the section being taken substantially on the line 6-5 of Fig.3;

Fig. 7 is an inside end view of the end plate carrying the exhaustvalve, this valve being shown in dotted lines; 1

Fig. 8 is a horizontal section through the end plate of Fig. 5substantially on the line 8-8 of that figure; V

Fig. 9 is an elevation of a preferred form of vane bearing;

Fig. 10 is an end view of the vane bearing of i 9;

Fig. 11 is a plan view showing the slot in the bottom of this bearing;

Fig. 12 is a side view of the preferred form of vane which forms animportant feature of the invention and which cooperates with the bearingshown in Figs. 9, 10 and 11;

Fig. 13 is a detailed plan view of the pump rotor showing the oil ductsand the support for the vanebearing of Figs. 9, l0, and 11;

Fig. 14 is a section substantially 0n the line iii-44- of Fig. 13;

Fig. 15 is a detailed perspective view of the preferred form of vaneshowing its relation to the novel type of vane bearing, and to the endplates of the machine;

Fig. 16 is a perspective view of a modified form of vane bearing andvane showing thev manner of supporting the bearing in the end plates ofthe machine and its relation to the vane;

Figs. 17, 18, and 19 are diagrammatic views showing the mathematicalrelation of the parts of apparatus embodying the present invention andcomparing the relation of those parts to apparatus of the same generalcharacter taken from the prior art.

Referring now to the drawings and particularly to Fig. 2, this figureshows a complete unit in which the pump is enclosed within the rotor ofan electric motor, preferably of the induction type adapted to operateon ordinary single phase alternating current. It is to be understoodthat although the invention has been illustrated in.

the form of a combination pump and. electric motor, the novel featuresof the pump are capable of general application, and may be applied inother relations using other driving'means. and

further that the structure can be utilized as a motor as well as a pumpit pressure medium is supplied to it in proper manner.

In Fig. 2 reference character 25 designates a flat base carrying aninverted bell-shaped housing 26 which may be set over it and preferablysecured'to it by welding peripherally as at 21. As here shown, thehousing 28 carries a series of heat dissipating elements 28 secured tothe casing at spaced intervals indicated 28 in the drawings.

Mounted within the casing is a stator ii of an electric motor made up asis usual of laminations designed to provide minimum magnetic reluctanceand freedom from eddy current losses. Disposed around the statorlaminations ii are stator windings 82 which will usually be made up intwo sections to provide for starting'and running conditions. While theparticular type types will be found useful in the present relation,

it is preferred to use a motor of the capacitor type operating on thesquirrel cage induction principle. A motor of this type lends itselfreadily to the present application because of the absence of movablemechanical parts, such as commutator short circuiting means. and itsability to utilize the metal structure of the pump cylinder as a supportfor the induction bars. For commercial installations where polyphasealternating current is available, a. motor of axial air gap constructionwill be found applicable in simplifying the arrangement.

In the drawing the rotor of the electric motor is indicated at 34 asmade up of a plurality of stacked laminations, supported between twospaced parallel and rings 35, preferably secured in position byinduction heating, using some low melting point conducting metal such assilver. An arrangement of this character simplifies the constructionbecause it reduces the time and cost of manufacture and provides forcomplete freedom from damaging the operating parts of the motor by, theapplication of excessive heat. The conductor bars which join the endrings 35 are indicated in Fig. 4 by the reference character 36, and itwill be understood that they are spaced circumferentially around therotor in accordance with usual practice in order to provide adequatetorque while insuring operating efficiency. The circuit for the statorwindings has not been indicated because it forms no part of the presentinvention, being merely arranged to provide for the conduction ofcurrent to the windings 32 through binding posts or terminals such asare indicated at 33 in Fig 4.

The rotating parts of the machine are carried by a central shaft 3?which is attached to the base plate 25 of the housing by a stud bolt 3dpassing through a central aperture in the. plate 25 and having a reducedthreaded section 89 threaded into a correspondingly threaded portion ofthe lower end of shaft 37. The upper end of the shaft 3i terminates withthe housing 25 to which it is secured by a hollow bolt M having anexternal threaded portion t2 which cooperates with an internallythreaded bore in the upper end .of the shaft. The belt 3i contains abore 63 the casing. The shaft adjacent its lower end carries a set ofspiral grooves 43 serving for oil distribution in the usual manner. Thecentral portion of the shaft 31 carries an eccentric 4'! containing atransverse opening 48 connecting the bore 44 with an eccentriclongitudinal bore 49 closed at the top but containing transverseopenings 5|, also serving for oil distribution and including peripheralgrooves at the terminal ends of these openings. The parts 5| when filledwith oil not only perform a lubricating function but also provide asealing action between these moving parts to prevent pressure leakagefrom the pump chamber.

As indicated above, the shaft 31 carrying the eccentric 41 is stationaryand serves as a bearing for the rotating parts of the pump. Referringespecially to Fig. 1, the outer rotating cylinder comprising an annular'metal member is desig-. nated 52. This cylinder is preferably ofnonmagnetic material such as brass or the like, and carries projectingradially inward from its inside surface and rigidly secured to it a vane53. This vane, as indicated in detail in Fig. 12, is roughly of T-shapedformation and comprises a body 53 and an extension 58. The body 53, asshown in detail in Fig. 15, is wider than the extension and theextension projects centrally of the width of the body and from the innerend of the vane to 'make the vane symmetrical.

The body carries mounting lugs 82 to hold it stationary and the bodyportions 80' extend into the end plates to assist this action. This vaneis especially designed as indicated above .for cooperation with a vanebearing 54 mounted in an opening 55 in the outer rim of rotor member'56. The rotor 56 is journaled to rotate about the eccentric 41 withwhich it is longitudinally coextensive as indicated in Fig. 2. Thisrotor is hollow and provides a lubricant chamber as indicated at 51 inFig. 14. In addition, this hollow portion of the rotor member reducesthe weight, and consequently the inertia, and provides clearance for themotion of the extension 58 provided on the vane 53. In other words,making the rotor hollow performs a three-fold function, namely, it formsan oil reservoir, reduces the weight, and avoids the necessity ofmachining operations to provide clearance for the movement of theextension 58 on the radial vane. This rotor, which is shown in detail inFig. 3, also carries on each of its lateral faces an annular groove 59serving for oil distribution and joining the opening 55 which carriesthe vane bearing 54. Inasmuch as it is highly desirable that this rotorbe dynamically balanced, it contains a series of openings 3|conveniently cut in the top groove 59-so as to compensate for theremoval of metal in forming the opening 55. Consequently when the vanebearing 54 is in position in the opening 55, the rotor with this bearingis dynamically balanced for smooth and efficient operation.

The cylinder 52 is attached to the rotor member 34 of the electric motoras herein shown with an interposed blanket 50 of heat insulatingmaterial. The electric rotor 34 during motor operation generates heat.Since the pump during the compression of gas necessarily generates heat,and it is desirable to keep the heat in the gas down to a minimum, theblanket 50 which may be of any poor heat conductor, with or without anair gap, will serve as a wall to isolate the motor rotor and thecylinder from each other. In some instances an air gap alone may servethis purpose without the addition of other heat insulating means. Inthis way the operating efflciency of the pump may be kept at a maximumso far as the accumulation of heat is concerned. This cylinder is closedat its lower end by an end plate 32 shown in detail in Figs. 6 and '7.This end plate may be sealed to the cylinder 52 and carries a downwardlyextending projection 63 which serves as a journal for the pump incooperation with the shaft 31 and the oil groove 46 thereon. Theextension 63 contains the radial grooves 45 on its lower face and issupported by a thrust bearing comprising upper and lower races 64 and 65with interposed ball bearings '66. This end plate, when secured to thecylinder 52 to enclose the rotor as by welding at 61, provides the lowerportion of the pump chamber, seal except for the lubricant passagewayformed by the grooves 45 and the oil duct 44 within the shaft 31. Asindicated in the face view of Fig. '7, end plate 62 contains a dischargeorifice 68 closed by a spring pressed discharge valve 69 which issecured to the end plate as at H. Reference to Fig. 6 will indicate howthis valve controls the discharge from the pressure chamber of the pump,and how the bias of the spring maintains the valve closed until the pumppressure has built up to a predetermined value. Consequently this valvealso serves as a check valve to prevent backfiow of gas from the dome tothe pressure chamber of the pump.

The top side of the pump chamber is closed by an end plate 12 shown inside elevation in Fig. 5 and in section in Fig. 8. This end plate fitsclosely within the cylinder 52 and may conveniently be welded to it insealing relation as indicated in respect to the end plate 62. This endplate contains a journal portion 13 adapted to embrace the upper portionof shaft 3! above the eccentric 41 and an annular chamber 14.

The bore in this end plate communicates with the' duct 43 arranged forthe intake fitting. Communication between the duct 43 and the intakechamber of the pump is provided by bore 30 in the upper end of shaft 31and a lateral port 40 which registers withv the annular chamber 14 inthe end plate 12. This annular chamber, communicating in turn with alongitudinal bore 15 and a second bore 16 terminating at the inner faceof the end plate, provides communication between the gas inlet and theintake chamber of the pump. The path for the gas will be apparent fromFig. 6 of the drawing. It will be seen, therefore, from Figs. 4 and 6that gas entering the inlet 43 can pass through duct 30 and port 40through the end plate to the intake chamber of the pump, and aftercompression there will reach the pressure chamber and discharge throughthe port 68 and the valve 69 into the dome provided in the housing 26and thence to a discharge pipe indicated at 17.

A characteristic of pumps of the present type has been that duringrotation of the cylinder and rotor there is a rocking movement of thevane and its bearing with attendant wear. The present invention avoidsthis by providing the lugs 82 on the vane 53 which are set in sockets inthe end plates and then having the ends of the vane also project intoopenings in the end plates so that the cylinder, the vane, and-the twoend plates constitute one unitary structure. This not only givesrigidity to the structure but avoids wear which would occur if the vaneand its hearmg were allowed to rock in the usual manner.

As indicated above, an outstanding feature of the present invention isthe construction or the vane 83 and its cooperating vane bearing Bl.Throughthe peculiar formation and cooperation of these elements, it ispossible to materially increase the displacement of the pump, over priorart constructions of this same general type. For example, as suggestedabove, the vane 53 is generally of T-shaped form having a centralextension 58. The bearing 54, on the other hand, is

- roughly cylindrical in form in order to fit closely in the opening 55in rotor 55. During the operation of the pump the rotor 58 rocks on thevane bearing 54. This cylindrical member 54 contains a longitudinal slotor groove 78 extending throughout its length on the side through whichthe vane 83 projects into it with the parts assembled in the pump. Thefloor of the groove l8 contains a slot 19 long enough to accommodate theextension 58 on the vane 58 when the two parts are assembled asindicated in Fig. 15 of the drawing. The slot 19 is disposed centrallybetween the ends of the groove 18 and; as shown, closely engages thelateral faces of the vane 63 so as to provide the required sealingaction. The ends of the slot do not engage the ends of the extensionbecause oil must pass freely through this space as the extension movesinto the slot. This relation of parts is clearly shown in Figs. 3 and 4of the drawings. In addition, the bottom ends of the bearing M are cutaway as at St to form lubricant pockets in cooperation with the walls ofopening 55.

It will be. apparent from an inspection of Fig. 15 that the body portionof the vane 53 is longer than the cylindrical bearing 5t so as toproject into the end plates. The body portion 53 completely fills thegroove 18, whereas the extension 88' works in the slot 19 and extendsthrough it as indicated in dotted lines in Fig. 3 with the end clearanceindicated in Fig. 4. Rigidity of the vane 53 is assured by its beingsecurely mounted in the slotted portion of the cylinder 52. and by thelugs 82 which are supported in the end plates 72 and 62 as described.

As indicated above, an important feature and one which is outstandingwith respect to the prior art, is the provision of a construction inwhich not only is the vane and the cooperating vane bearing preventedfrom any rocking movement, but the volumetric capacity of the pump isconsiderably enhanced over what constructions of the prior art permit.As set forth above, this may be accomplished by the use of peculiar vaneand vane bearing construction such as that which has already beendescribed. While that arrangement effectively prevents any rocking orcanting of the vane and its bearing, an alternative manner in which thismay be accomplished is that shown in Fig. 16 of the drawing.

Referring now to Fig. 16, the reference characters 83 and 6d designatethe two end plates which are attached to the cylinder to seal thelateral sides of the pump chambers. These plates on their inner facescontain peripheral slots 85 adapted to receive and rigidly support lugs88 carried by a vane bearing 86. As shown, each end of thisbearingcarries two spaced lugs 88. the spacing being such as to form agroove 8| and accommodate with a close fit the body portion of a vane 39having a length sufficient to extend between the projecting bosses 88and guided in a rigid straightline movement. The portions of the vanethat are coextensive with lugs 88 are designated 93 in the drawing. Thetop edge of the vane 86 carries lugs 92 which fit into the cylinder andspecifically into slots out therein similarly to the lugs 82 on vane 53.In this way, as in the former construction, the vane and the bearing areheld rigidly in posiiton so that there is no possibility of canting orrocking movement of these parts during the operation of the pump. Itwill be noted; furthermore, that the vane bearing 86 is not onlysupported at its two ends in the sockets in the end plates 83 and 84,but the floor of the groove 9i which receives the body of the vane 89 issolid as indicated by the dotted lines at 81. As will be pointed outhereinafter with respect to the diagrammatic views of Figs. l7, l8 and19, this construction permits increase in capacity of the pump withoutreducing the metal sections to an undesired value. Accordingly, thisarrangement offers all of the advantages which have been set forth inconnection with the preferred construction already descrihed. and evenprovides for a further increase in capacity over that construction.

It has been-indicated that practice of the present invention greatlyincreases the amount of pump displacement which can be obtained with astructure of given size. This will be apparent from detailedconsideration of Figs. 17, 18 and 19 wherein diagrammatic views are usedto indicate the critical factors in the design of a pump of this type,both according to prior art teaching and according to the novelstructure of the present invention.

grammatically a radial vane pump employing a rectangular vane in whichthe vane in its retracted position always remains slightiy below thegeometrical center of the vane bearing in order to give it stability. Inthis figure lllil represents the maximum clearance between the rotor andcylinder when the vane lot is retracted to its greatest extent. Hi2represents the vane bearing having a slot 803, the diameter of the vanebearing being indicated N. V represents the distance which the vane iiliextends below the center of the vane bearing in the fully retractedposition of the vane. M represents the space between the bottom of thevane IUI in its fully retracted position, and the bottom of the slotnot. W represents the section of metal which is left in the vane bearingafter cutting the slot m3, this being one of the critical factorsinvolved in producing a strong structure of the present type. werepresents the shaft carrying the eccentric N35. The section of metalbetween the vane bearing I02 and the shaft is indicated Q. S representsthe radius of the shaft and A the space between the center of theeccentric R represents the in the arrangement of Fig. 17, if it isassumed that the radius of the pump cylinder is six inches, that soundengineering practice is followed in never retracting the vane lfiioutwardly beyond the center of vane bearing .802, and that adequatemetal sections W and Q are maintained, that the maximum pumpdisplacement for a pump having a chamber length of 4 inches would be168.8612 cubic inches per revolution. In this calculation on Fig. 17,the following dimensions in inches are assumed:

R=6 X=1.25 S=0.5 V=0.25 Q=O.5 A=0.625 W=0.375 M2125 N=0.5

With the T-shaped vane shown in Fig. 18. following the practiceindicated above and never allowing the inner end of the extension 58 ofthe T-shaped vane to be withdrawn beyond the point I06, the displacementwould be 235.9626 cubic inches per revolution. Here the assumeddimensions are:

R=6 X=1.850 S=0.5 V=absent Q=0.925 A=0.925. W=0.3'75 M=1.850 N=0.5

It is to be noted in this connection that the metal section W is thesame in both constructions of Figs 17 and 18, and, even thoughstructurally different, the efiective amount of metal in section Q issubstantially the same in both. Hence the construction of Fig. 18 notonly increases the pump capacity by 67.1 cubic inches per revolution,but it positively eliminates canting of the vane bearing with respect tothe vane and greatly enhances the life of the parts while insuringadequate sealing over long periods, and smoothness of operation whichcannot be achieved when canting occurs. I

Reference to Fig. 19 shows the displacement which can be obtained usingthe construction of Fig. 16 where the pump cylinder again has a radiusof 6 inches and the longitudinal dimension of the pump chamber is 4inches. The displacement here is 257.5620 cubic inches per revolution oran increase over the construction of Fig. 17 of 88.3 cubic inches perrevolution. The dimensions assumed in Fig. 19 are:

Here the metal sections W and Q are the same as those indicated in Fig.17, and the vane 89 can be withdrawn beyond the center of the vanebearing 86 because this hearing is rigidly supported by the end lugs 88in the end plates of the pump chamber. vents any possible canting of thevane bearing and hence again insures smooth, precise, and wear-freeoperation of the parts over long periods.

It will be clearly apparent and can be substantiated by mathematicalproof that the embodiment set forth in the present specificationprovides a highly effective mechanism for obtaining maximum pumpdisplacement with a minimum of structural parts, and with completefreedom from the usual pump leakage which is encouraged by rockingaction of a vane with respect to its bearing; The space within thehousing 26 serves as a receiver for pressure which is built up and whichleads through the outlet H to the mechanism to be supplied with fluidunder pressure. The casing contains oil which may usually be kept at thelevel indicated by dotted lines in Figs. 2

This manner of mounting pre-.

. 10 and 4 so th'atthe inherent operation of the pump will supply thelubrication.

When the cylinder 52 is rotated as by supplying current to the statorwindings of the electric motor, this cylinder rotates, carrying with itthe vane 53 and the rotor 56, with the vane 53 moving out and in thegroove I8 in the vane bearing 54. Gas will enter the intake 43 and afterpassing through the bore 38 and the lateral passage 48 will be deliveredto the intake chamber on the upper side of vane 53 as indicated in Fig.1

of the drawing, and then as the cylinder rotates in a clockwisedirection this gas will be compressed until it escapes through thedischarge valve 68 to the space within the pump chamber and then to thedischarge line H. The crescentshaped chamber will always be divided intotwo parts by the tangential contact between the retor 56 and the insideface of cylinder 52, and also by the vane 53. As has already beenindicated. whenever the pressure in the pressure chamber of the pumpexceeds the tension of spring 69, the discharge valve 68 will open,allowing the escape of gas under pressure, but preventing return flowinto the pressure chamber of the pump. When, onthe other hand, thepressure in the pressure chamber of the pump is less than the tension ofspring 69, this valve remains closed. I

It will be obvious that as the pump cylinder rotates, the pressure onthe intake side of the pump will be less than the dome pressure, thatis, the pressure inside of the housing. Hence, there will be a constanttendency for this pressure difierential to cause flow of oil through thelateral openings 45 in the shaft extension 63, and through the duct 44and space 48 to the interior of the rotor. Oil will also travel from thespace 48 through the duct 49 and th'ence through the lateral ports intothe spaces 5| between. the journal 13 of the top end plate and the shaftextension. .It will be noted that the extension 58 on the vane never iswithdrawn beyond the center of the vane bearing 54, thus furtherassuring maintenance of straightline movement.

When the vane is moved from the fully retracted position of Figs. 1 and2 to the position shown in Figs. 3 and 4, the extension 58 will forceoil back into the oil spaces, insuring a continuous flow to the parts tobe lubricated and also displacing oil from the top of the rotor into thegroove 59 where it forms a fluid seal between the sides of the rotor andthe two end plates 52 and i2. Thus it is possible to both lubricateandseal the pump by the inherent action of the pump parts and without theprovision of any extraneous pumping means whatsoever. It thereforebecomes possible to utilize the flow resulting from the difierentialbetween so-called dome pressure and intake pressure to fully lubricateand seal the working parts of the pump, It is therefore unnecessary toprovide pumping means to increase the pressure above dome pressure.

It will be observed that the insulating means 50, be it in the form of ablanket or an air gap or both, will prevent any heat generated in thelaminated structure 34 of the motor rotor from passing into the pump inorder to increase the temperature of the gas which is under compressionthere. This freedom from heating up will likewise be enhanced when thepump cylinder 52 is made of non-magnetic metal in which no eddy currentscan be produced.

It has been suggested above that the present construction makes itreadily possible to utilize 52 may be varied in order to vary thediameter of the pump chamber. Likewise, variation in the thickness ofthe two end plates '82 and 12 will permit a substantial change in thelongitudinal dimension of the pump without in any way altering the sizeof the mechanical parts oi the electric motor. Since the pump operatesat high speed, a very small change in longitudinal or radial dimensionswill produce a substantial change in the pump capacity. Thus it will bepossible by a single casing and motor struc- 15 ture to provide for aconsiderable number of pump capacities. Bysuitable design of the rotorand stator laminations a single laminated structure may be utilized forseveral sizes of pump.

If the pump capacity is to be increased beyond 9 the capacity of thewindings, a simple change in the winding construction utilizing the samelaminations may be provided so as to accomplish the results sought,namely, a universal motor and pump structure in which various sizes ofpumps may be substituted directly-in a given laminated constructionwithout making it necessary for a great number of different part sizesto be carried.

Although only a few modifications .have been described, it will beobvious that various changes and modifications of the invention may bemade within the scope of the appended claims without departing from thespirit and scope of the invention. Having thus described the invention,as

what is claimed is:

1. A positive displacement radial vane pump comprisinga fixed shaft, ahollow pump cylinder rotatable on said shaft, a pump rotor mountedeccentrically with respect to said shaft so as to maintain a point oftangency between its periphcry and the inner surface of the cylinder asthe cylinder and rotor rotate, said rotor having an internal annulargroove forming an annular chamber about said shaft and said rotor alsoas having a vane bearing opening extending through the periphery of therotor at one point and communicating interiorly with said annulargroove, a cylindrical vane bearing mounted in said rotor with a portionof the periphery of co the bearing exposed through said one point, saidbearing containing an exposed longitudinal roove throughout its lengthand a central elongated slot in the bottom of said groove, and a vanesecured to said cylinder and extending radially inward therefrom, saidvane having a wide body portion movable in the groove in said vanebearing, and a central extension projecting through the slot in thebottom of the groove with its sides in close sealing contact with the msides ofsaid slot but with its ends spaced from the ends of the slot,said central extension being freely movable, into the annular groove insaid rotor when the wide portion of the vane approaches the bottom ofthe groove in the vane bearing.

2. A pump of the radial vane positive displacement type comprising asymmetrically rotatable hollow cylinder having a radial vane extendinginwardly therefrom, said vane having a wide body and a centralprojection, a symmetrically rotatable dynamically balanced hollow rotorhaving a cylindrical bearing receiving portion exposed at the peripheryof the rotor and communicating with the hollow interior of the rotor,said rotor being mounted within said cylinder in eccentric relation tosaid cylinder, a stationary shaft for supporting said rotor andcylinder, said shaft having a bore therein communicating with the hollowinterior of the rotor, a cylindrical vane bearing mounted in saidbearing receiving portion of the rotor, said bearing having an exposedlongitudinal groove to receive the wide body of the vane and acentralelongated slot in the bottom of the groove to receive the projection onsaid vane, the sides of said slot closely engaging the sides of saidvane but the ends of the slot being spaced from the edges of said vane,the projection on said vane being adapted to move in and out of saidhollow rotor through said central slot as the cylinder and rotor rotate,a housing enclosing said cylinder, rotor and parts before mentioned, andconnections for causing the pressure differential between the interiorof said rotor and the interior of the housing to supply oil from thebottom of said housing through the bore in said shaft to said hollowrotor, said projection in its movement into and out of said hollow rotorserving to displace oil therefrom.

HARRY B. MILLER.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 395,646 BaileyJan. 1, 1889 395,647 Bailey Jan. 1, 1889 1,081,687 McLane Dec. 16, 19131,441,344 Hatcher Jan. 9, 1923 1,439,077 Hatcher- Apr. 1, 1924 1,780,338Canton Nov. 4, 1930 2,246,271 Davidson June 17, 1941 2,246,274 DavidsonJune 17, 1941 2,246,275 Davidson June 1'7, 1941 2,246,278 Wishart June17, 1941 2,415,011 Hubacker Jan. 28, 1947 FOREIGN PATENTS Number CountryDate 394,263 Great Britain June 22, 1933 512,250 Great Britain Aug. 31,1939

